The use of plastic cards bearing a magnetic stripe for effecting sales, banking, and other diverse transactions is very popular, in part because of the ease with which such cards may be legitimately used to effect these transactions, and because of the ubiquitous infrastructure that makes their use possible.
A magnetic stripe on a card enables the card to be swiped repeatedly in a card reader and convey the digital information stored on the stripe to that reader. The information on a magnetic stripe is written onto the stripe by a magnetic write-head, similar to the way digital information is written onto a magnetic tape. Writing onto the magnetic stripe requires that the write-head moves relative to the stripe while generating a variable bipolar magnetic field that represents the data to be stored, and magnetizes the particles along the stripe accordingly. The magnetic stripe material typically in the form of a slurry is deposited on a card, ticket, or other item in a similar way as paint is deposited on a surface. The magnetic particles retain the memory of their last direction of the magnetic polarity until a magnetic field strong enough to overcome the particle's coercive force changes the polarity to a new direction.
The American National Standards Institute (ANSI) & ISO/IEC has defined standards relating to magnetic stripe cards.
A typical magnetic stripe is segmented into four channels, three of which are defined for a specific format by ANSI. These tracks are defined only by their location on the magnetic stripe. Each is dedicated to a different purpose:
Track one contains the cardholder's name as well as account and other discretionary data
Track two contains the cardholder's account number, encrypted Personal Identification Numbers (PIN), finger print characteristics, and other discretionary data. This track is the most commonly used and is read by Automatic Teller Machines (ATM) and credit card checkers
Track 3 is unique and rarely used.
Most ATM cards follow these standards, but there are many other types of cards (key cards, security cards, copy machine cards, etc.) that do not follow these established standards.
Smart cards refer to cards that typically include embedded input/output interface, memory, and a microprocessor. Smart cards look like standard plastic cards, but are equipped with embedded Integrated Circuit(s). Smart cards can store information, execute local processing on data, and interface with external devices. These cards take the form of either “contact” cards that require an electrical connection to an external card interface (Card Acceptance Device (CAD)) or “contactless” cards that communicate by electromagnetic signals to the external card interface (CAD). The contact card typically has eight metallic interface pads on its surface, each designed to international standards for VCC (power supply voltage), RST (used to reset the microprocessor of the smart card), CLK (clock signal), GND (ground), VPP (programming or write voltage), and I/O (serial input/output line). Two pads are reserved for future use (RFU). Only the I/O and GND contacts are mandatory on a card to meet international standards; the other contacts are optional.
When a smart card is inserted into a Card Acceptance Device or CAD (such as a point-of-sale terminal), the metallic pads come into contact with the CAD's corresponding metallic pins, thereby allowing the card and CAD to communicate. Smart cards are reset when they are inserted into a CAD. This action causes the smart card to respond by sending an “Answer-to-Reset” (ATR) message, which informs the CAD of what rules govern communication with the card and the processing of a transaction.
Note that in the context of the invention, smart cards are not bound to the structure and manner of operation discussed above. Thus, for example, contact smart cards are not bound by the particular standard described above, and this applies also to contactless cards. By way of another example, smart cards are not bound by any specific substrate, such as plastic cards.
Notwithstanding the advantages of smart cards over magnetic cards, the adoption of smart cards has been relatively slow in the US and other leading markets. One of the main reasons for their slow adoption is the present lack of support infrastructure (e.g. dedicated readers), necessitating retrofitting of equipment such as vending machines, ATMs, and telephones to incorporate dedicated readers that are adapted to read smart cards and possibly also write data thereon.
The standard “non-smart” magnetic stripe cards, on the other hand, enjoy a ubiquitous infrastructure in many commercial, access control, and other applications and notwithstanding their inferiority compared to smart cards, consumers use predominantly magnetic cards.
The invention according to the PCT publication WO 01/88659 (hereinafter the PCT publication) combines the inherent advantages of smart cards with the widely circulated magnetic card readers. PCT WO 01/88659 discloses an electronic card that can function as an anonymous credit card or banking card for use on or off the Internet, and which utilizes a magnetic storage medium affixed to the card that can be read by a standard magnetic stripe reader. An encoder generates a data packet that can be stored in a designated portion of the magnetic storage medium, which can be a magnetic stripe. The data packet can contain a personal coupon and an alias. A computer or microprocessor generates the personal coupon after a Personal Identification Number is input into the card. The data packet can also be used to convey other information, such as a low battery condition. Several different methods of customizing use of the electronic card provide a vast array of options for handling multiple users, bills, and accounts; and for characterizing individual transactions of the card.
The device disclosed in the '659 publication offers backward compatibility in the sense that information stored in or generated by the smart card and stored in track #2 of the magnetic stripe is accessible by conventional magnetic card readers. The backward compatibility allows the users and industry to benefit from the widely circulated and reliable infrastructure of the magnetic cards readers, and obviates the need for extensive and expensive retrofit, as would be required with conventional smart cards using dedicated smart card readers.
Some of the principles of operation which relate to the PCT application, and which serve as a background for understanding the invention, will be explained with reference to FIGS. 1 to 3. FIG. 1 shows current flowing through a conductor 4 (illustrated in cross-section front view in FIG. 1) that generates magnetic field 6 of strength H (around the conductor 4). The strength of the magnetic field H complies with the following algorithmic expression:
  H  =      I    R  
Where: I is the current in the conductor and R is the radius (distance) from the center of the conductor 4 to the location of interest where magnetic field 6 H is measured. The direction of the magnetic field 6 H is clockwise as indicated by the arrows on the magnetic field lines 6, and corresponds to a current direction in the conductor 4 that is perpendicular to the page and flows in a direction from the viewer into the page.
As is further shown in FIG. 1, a thin magnetic stripe layer segment 2 is located in close proximity to the conductor 4. The flow through the conductor imposes a magnetic field with polarity of North Pole (N) and South Pole (S), as indicated in FIG. 1. The SN poles illustrated in. FIG. 1 constitute a magnetic domain; each track in the magnetic stripe layer includes a plurality of magnetic domains in a line. When the current direction is reversed in a direction from the page to the viewer, the direction of the magnetic field is reversed to counterclockwise, and so are the S and N polarities on the magnetic stripe (not shown). The magnetic field strength 6 must be intense enough to overcome the coercivity of the magnetic stripe 2 material. Since the magnetic field is proportional to the current in the conductor 4, it is necessary to reach a balance between the magnitude of the current pulse and the coercivity of the magnetic material. Once the magnetic polarity on the magnetic stripe 2 has been set by the current, the current flow can be stopped and the imprint on the magnetic stripe will remain in that setting until reversed by a reverse current in the conductor 4 or by an external magnetic field that is strong enough to overcome the coercivity of the magnetic stripe 2. Thus, current impulses of the right magnitude and direction are sufficient to imprint data on the magnetic stripe material.
Note that it is desirable to minimize the magnitude of the current pulses so that currents and their current drivers become manageable. However, the lower the coercivity of the magnetic stripe material, the more susceptible is the magnetic stripe to being inadvertently modified by external magnetic fields.
FIG. 2 illustrates a typical card 10 with a magnetic stripe and four channel (tracks) 20, 30, 40, and 50. The resolution of such a magnetic stripe varies and some standards suggest 75 and 210 bits per inch of data density.
FIG. 3a shows a schematic view of a segment of one channel of the associated magnetic stripe 70 of a smart card. Items 80a, 80b, and 80c, drawn in dotted lines, represent the conductors in a layer below the magnetic stripe 70. Note that the distance between the conductors determines the maximal bit density possible. For example, for a resolution that will accommodate 210 bits per inch, at least 210 conductors per inch must be constructed.
FIG. 3B illustrates a cross-section view along AA of the segment depicted in FIG. 3A, in which 80a, 80b, and 80c are the conductors with insulating material 75 between them, while on top of them is located the magnetic stripe 70.
FIG. 3C illustrates a cross-section view along BB of the segment depicted in FIG. 3A in which the leads 82a and 82b are made available for connections between the conductor 80c and a current delivery and switching drivers.
The principles described with reference to FIGS. 1 to 3 above are suitable for integration with a smart card. The current drivers deliver the currents necessary to write and rewrite the data content of the smart card's magnetic stripe, in accordance with the conceptual approach described with reference to FIG. 1. The smart card's direct writing is initiated by external command inputs to the smart card or by, for example, stroke(s) on the card's keyboard. After having written the data on the magnetic stripe, when the smart card is swiped in a standard magnetic stripe reader, the last data written will be available to the reader.
To summerize, FIG. 3A, FIG. 3B and FIG. 3C, track # 2 of magnetic stripe 70 is part of a standard credit card, and the conductors 80a, 80b, and 80c as well as the insulator 75 are part of the smart card (as described in the PCT publication).
There are also provided appropriate electronics and current drivers. The object bearing the magnetic stripe 70, for example, a credit card is placed in close proximity to the conductors 80a, 80b, and 80c as seen in FIG. 3b, all forming part of the card. Currents through the conductors 80a, 80b, and 80c induce the data information onto the stripe.
A smart card of the kind described generally in FIGS. 1 to 3 is disclosed in the '659 PCT publication but it purports only to offer an improved smart card which facilitates digital data transformation into a format that is compatible with the standard magnetic stripe reader. One of the significant disadvantages of the smart card disclosed in the '659 publication is the use of a many conductors and a cumbersome electronic system including current drivers in order to facilitate data writing onto the magnetic stripe. Such a cumbersome electronic system (as will be explained with greater detail below) poses high manufacturing costs and consumes battery power, thereby hindering the wide circulation into the marketplace of a smart card of the kind disclosed in the '659 publication.
For a better understanding of the cumbersome structure of the electronics system and drivers in accordance with the PCT publication, there follows a description of a “write bit” operation (of bit value ‘0’ or ‘1’), including flip bit value (from ‘1’ to ‘0’ or vise versa) and “read bit” operation.
Thus, and as depicted in FIG. 7D of the '659 publication (attached herewith and marked as 3D), each bit is represented by two magnetic domains (each being imposed to either SN or NS magnetic orientation). As may be recalled, the description with reference to FIG. 1, above, exemplified the correspondence between current flow direction in the conductor and corresponding magnetic orientation (SN or NS) per domain.
As depicted in FIG. 7D, each domain is associated with two conductors, which, depending upon the direction of the currents flowing through the respective conductors (e.g. 34 and 35 of FIG. 7D), will impose the polarity of the magnetic domain to NS or SN (using basically the concept described in FIG. 1, above).
Generally speaking, when the current flows in a prescribed direction through the two conductors associated with a given magnetic domain (say 34 and 35 in FIG. 7D), it imposes a polarity NS. Similarly, the polarity of the mating magnetic domain is also imposed to NS (using current flowing in the same prescribed direction through its respective two conductors). Given two successive NS domains written in the manner specified current direction, (i.e. the polarity of each one of the mating magnetic domains is imposed to NS), when a conventional magnetic reader reads the succession of NS and NS (i.e. the neighboring magnetic domain have the same magnetic orientation), there is no flux reversal (i.e. the magnetic reader regards the two consecutive domains as a single NS), and thus indicates a bit value of ‘0’. Similarly, when the magnetic card reader reads a succession of SN and SN (where, during a preceding writing phase, each SN was imposed on a magnetic domain by current flowing in prescribed direction through the respective two conductors associated with the magnetic domain), it also indicates a bit value of ‘0’, since here also there is no flux reversal. In contrast, when the magnetic orientation of a first magnetic domain is SN and the magnetic orientation of the neighboring domain is opposite (NS), the magnetic reader senses flux reversal between the neighboring domains, and this is interpreted as ‘1’. By the same principle two opposite magnetic orientations NS followed by SN, will likewise give rise to flux reversal (sensed by the reader) and will be interpreted as ‘1’.
The encoding of ‘0’ and ‘1’ in the manner specified is illustrated in FIG. 7B of the PCT publication (attached herewith and marked as 3E) where, as shown, consecutive domains with identical magnetic orientation (NS, NS or SN, SN) are interpreted as ‘0’ (see, for example, the first raw of the specified FIG. 7B), whereas consecutive magnetic domains with opposite magnetic orientation (NS, SN or SN, NS) are interpreted as ‘1’. Note that the frequency of ‘1’ (e.g. the second raw of FIG. 7B) is twice the frequency of the ‘0’ (e.g. the first raw of FIG. 7B), in accordance with the Aiken Biphase code discussed in the PCT publication.
In accordance with the PCT publication, two conductors are used per domain, giving rise to four conductors per each bit. The use of two conductors per domain and associated electronics, as described in the '659 publication, facilitates relatively rapid writing and changing of current flow direction (through the conductor(s)) whenever flipping polarity is required (i.e. when a bit value needs to be inversed from ‘1’ to ‘0’ or vise versa). This writing and flipping polarity is achieved at the cost of using a cumbersome system that includes 4 conductors and associated electronics per bit. The associated electronics include current drivers that employ one transistor per conductor. Considering that a relatively high current is required to overcome the magnetic coercivity of the magnetic domain (whenever flipping the polarity is required), the so utilized transistor should sustain currents of relatively high magnitudes, requiring thus power transistors which consequently require larger real-estate on the board or silicon chip than low current transistors do.
As may be recalled, relatively high currents are utilized since the higher the current, the stronger the generated magnetic field, thereby reducing the prospects of undesired flipping of the magnetic domain's polarity due to influence of external magnetic fields.
Thus, for example, for a series of 500 bits that reside on the magnetic stripe, 2000 conductors and 2000 power transistors (used in the current drivers) are utilized. The description with reference to FIG. 8 of the 659 publication illustrates the complexity of a system of the kind specified.
Realizing such a cumbersome system in a chip that is incorporated in a card having dimensions of a conventional credit card is relatively expensive, because the conductors and associated electronic circuitry would require relatively large real-estate chip space, rendering the manufacture of such chips expensive. Note also that the more complicated the chip, the lesser the yield rate (i.e. the percentage of the fault free manufactured chips), giving rise to increased manufacturing costs, chip price, and the resulting smart card.
Note also that circuitry of the kind specified consumes battery power (due to the use of many current drivers, thus significantly reducing the lifespan of the card's battery, posing undue burden of the user who is compelled to frequently change or re-charge used batteries.
Note also that the switching mechanism of pulsed current in selectable directions into each individual conductor embedded in the magnetic stripe has been used in prior art in conjunction with, for example, magnetic core memory, and will therefore not be further expounded upon herein.
It is thus appreciated that the solution according to the '659 publication suffers from various shortcomings; accordingly there is a need in the art to provide for a novel backward-compatible solution of a smart card that can be used, inter alia, with conventional magnetic card readers. Such an improved smart card can be used, among other uses, to consolidate a plurality of credit cards into a single smart card.
There is a further need in the art for providing an improved smart card capable of static emulation of magnetic stripe, for use with conventional magnetic card readers.
There is still further need in the art for providing an improved smart card capable of dynamic emulation of magnetic stripe, for use with conventional magnetic card readers. There is still further need in the art to use such improved smart card in dual function, allowing also writing thereto using conventional magnetic card writer.
There is still further need in the art for providing a new type of magnetic card writer with no moving parts, configured to write data on magnetic stripes of conventional credit cards, for example.